The NHANES-Centers for Medicare & Medicaid Services (CMS) linked data files are restricted-use files that can only be accessed through the Research Data Center (RDC). The RDC is housed on-site at Centers for Disease Control and Prevention (CDC) facilities in Hyattsville, MD and Atlanta, GA. In addition, NCHS data can be accessed from RDCs housed in U.S. Census Bureau offices in several locations across the country. These RDCs provide researchers who have RDC-approved research proposals access to restricted data. Additional information on data requirements may be found in the guidelines, Procedures and Costs for Use of the Research Data Center, on the NCHS website. A link to the guidelines is located in the Resources section.
InformationRestricted access to the NHANES-CMS linked data in the RDC is due to the person-specific data that could permit the identity of a beneficiary to be deduced. Data with beneficiary identifiers are subject to the Privacy Act, Freedom of Information Act and other Federal government rules and regulations. As such, the information is confidential and is to be used only for reasons compatible with the purpose(s) for which the data are collected.
If you are interested in accessing the NHANES and CMS linked data files, you must submit a research proposal that outlines the need for this information. The proposal provides a framework for the RDC to identify potential disclosure risk.
It is important to use the feasibility files (discussed more fully in Module 5 [insert link to Module 5]) for determining the maximum available sample size so that the feasibility of conducting analyses utilizing the NHANES and CMS linked data can be assessed.
All proposals for NHANES and Medicare linked data should include a request for the CMS Medicare Denominator File for the years that the researcher is examining claims data. The Denominator File is needed to help construct the analytic sample, particularly to identify Medicare beneficiaries enrolled in a Medicare Part C plan, for whom traditional fee-for-service claims are not available. Medicare Part C plans are also referred to as Medicare Advantage (MA) and include Health Maintenance Organizations (HMOs), Managed Care Plans, Preferred Provider Organizations (PPOs), Private Fee-for-Service (PFFS) Plans, Special Needs Plans, and Medicare Medical Savings Account Plans.
All proposals for NHANES and Medicaid linked data should include a request for the CMS Medicaid Person Summary (PS) File for the years that the researcher is examining claims data.
Once the proposal is approved, RDC staff will work with you to create a data file specific to your research question. RDC staff prepares the data file which you may access at the RDC, remotely, or the RDC staff will run the analysis and email the results to you.
You should test any programming code, using public use data that you plan to submit to the RDC, to ensure its accuracy. You are responsible for creating your own ‘user supplied’ dataset, including SEQN, that will be merged with the CMS restricted-use linked data by the RDC staff.
InformationTo properly calculate variances you should include all observations from the specific years of NHANES as part of your analytic dataset.
There are several different ways to access data within the RDC, including remote, onsite, and staff assisted access.
The Resources section of this module provides a hyperlink to information regarding the RDC proposal process and different modes of accessing the NHANES-CMS linked data.
InformationRestricted access to the NHANES-CMS linked data in the RDC is due to the person-specific data that could permit the identity of a beneficiary to be deduced. Data with beneficiary identifiers are subject to the Privacy Act, Freedom of Information Act and other Federal government rules and regulations. As such, the information is confidential and is to be used only for reasons compatible with the purpose(s) for which the data are collected.
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